There are no must-win games in July. It's still too early in the schedule to look ahead to postseason previews. But based on the excitement in St. Louis and Oakland last night, we are in for a treat when the really big series do arrive later this summer.

There was a craziness to the O.co Coliseum for the start of the Bay Bridge Series that seemed at least equal to the intensity that A's fans showed when Yoenis Cespedes & Co. faced the Tigers in the playoffs the last two Octobers. Horns blew throughout the 5-0 victory over the Giants, who have had plenty of magical nights on their side of the bay this season.

This was more like winter ball or the World Baseball Classic than just another night in a 162-game season.

Instead of magic in the air, it was tension that hung over Busch Stadium.

With the Pirates in town for a rematch of last year's National League Division Series, playing well after a false start to the season, the Cardinals badly needed to hold serve behind ace Adam Wainwright. Neither team is in position to take any series lightly, especially not one against an NL Central rival.

There's still a chance that both the defending NL champs and the Pirates can win 90-plus games and return to the playoffs. But if they're going to move past Milwaukee and outplay Cincinnati over the 70 or so games that remain, they'll have to raise their level.

No one would be surprised if they did, but nobody really knows how the Central will resolve itself, which is the coolest thing of all for baseball fans. The strength of the Braves and Nationals atop the East and the Dodgers and Giants atop the West could leave room for only one Central team in the playoffs, and the battle to be the last one standing will be intense.

Some figured the Cardinals would cruise into the playoffs with their pitching intact from last season -- you know John Mozeliak and Mike Matheny knew it would be a fight, however, because it is always is -- but as recently as June 6, they were a .500 team and have climbed to 48-42, on pace for an 86-win season. That's not going to cut it.

But the good news is that the Cards are positioned to largely control their own fate. They have 32 games remaining against the top Central teams, including 13 against the Brew Crew.

Neither Wainwright nor the Bucs' Charlie Morton gave an inch last night, with Wainwright showing his mettle until his last pitch.

Wainwright wound up facing Andrew McCutchen with runners on first and second, two outs, in the seventh inning. He started him with a curveball, which McCutchen laid off for ball one. But he chased a 1-0 fastball that was outside and popped it up harmlessly to right fielder Allen Craig.

But the Cardinals were in a bigger jam the next inning. Clint Hurdle was resting ultra-productive rookie Gregory Polanco against Wainwright, but he sent him up to face St. Louis lefty Sam Freeman with two outs and the bases loaded in the eighth inning.

Freeman started Polanco with a ball but got him to a 1-2 count, which brought the fans to their feet at Busch Stadium. That's a sign that Cardinal Nation is in October mode, and Freeman rewarded the red-clad loyalists by inducing a weak swing and miss from Polanco on a low slider.

An inning later, Ol' Slippery Rock, Matt Adams, blasted the first walk-off homer for the Cards since 2011. It was the biggest moment in what has been a solid season for Adams, who moved in the lineup as a regular after Carlos Beltran's departure.

It's been a shock to see the deep St. Louis lineup struggle to score runs, but that hasn't been Adams' fault. He's hitting .331 with 10 homers. As is true for his team, though, there is some obvious room for improvement after the All-Star break.

Adams had drawn only eight walks to offset 56 strikeouts. He would have driven in more than 36 runs if he was batting higher than .232 with runners in scoring position. Adams is hitting only .203 against left-handers, although the blast into the right-field seats on Monday night came against Pirates lefty Justin Wilson. Maybe this will be the start of big things for him and the Cardinals.

The loss dropped the Bucs to 37-24 since May 2. Only two teams in the Major Leagues have been better in this stretch -- the Angels and the A's.

Something big is happening in Oakland. But don't believe me. Tune into Game 2 of the Bay Bridge series tonight -- Madison Bumgarner vs. Sonny Gray -- and you'll be able to feel it, no matter how many time zones away you might be.

Phil Rogers is a columnist for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.